/*
 * Copyright 2006 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package java.util;

public abstract class AbstractSet extends AbstractCollection implements Set {

  public boolean equals(Object o) {
    if (o == this)
      return true;

    if (!(o instanceof Set))
      return false;

    Set other = (Set) o;

    if (other.size() != size())
      return false;

    for (Iterator iter = other.iterator(); iter.hasNext();) {
      Object otherItem = iter.next();
      if (!contains(otherItem))
        return false;
    }
    return true;
  }

  public int hashCode() {
    int hashCode = 0;
    for (Iterator iter = iterator(); iter.hasNext();) {
      // Sets can have null members
      Object next = iter.next();
      if (next != null) {
        hashCode += next.hashCode();
      }
    }
    return hashCode;
  }

  public boolean removeAll(Collection c) {
    int size = size();
    if (size < c.size()) {
      // If the member of 'this' is in 'c', remove it from 'this'.
      //
      for (Iterator iter = iterator(); iter.hasNext();) {
        Object o = iter.next();
        if (c.contains(o))
          iter.remove();
      }
    } else {
      // Remove every member of 'c' from 'this'.
      //
      for (Iterator iter = c.iterator(); iter.hasNext();) {
        Object o = iter.next();
        remove(o);
      }
    }
    return (size != size());
  }

}
